OWOE Staff: The world recently celebrated Earth Day on April 22 - 52 years after the first Earth Day celebration in 1970. Unfortunately, like pretty much all the prior Earth Days, very little concrete progress was committed to addressing the world's global warming crisis. If I may paraphrase my favorite environmentalist, Greta Thunberg, it was all "bunny, bunny…blah, blah, blah". Perhaps the biggest news in the fight against climate changes was Denmark's proposal for a new corporate carbon tax, which would set a value of 1,125 Danish crowns ($164.21) per tonne of carbon equivalent and make it the highest such tax in the world if implemented. But again, that’s just a proposal. In the meantime, fossil fuel use has recovered from its Covid lows, CO2 levels in the atmosphere continue to rise, the Arctic and Antarctic ice sheets continue to melt, and environmental damage from storms, fires, and rising sea levels continue. I personally witnessed a real-life example of that the very week of Earth Day when I visited one of my favorite beaches in the world, Cancun. I have been going to the beaches of Cancun almost every year since the early 2000s, and the change to the beach caused by the increase in seaweed over the past few years is dramatic. We all tend to miss the big picture when all we see are incremental changes, but after skipping two years because of pandemic travel restrictions, the magnitude of the beach changes was more obvious and led me to look back at my earlier visits and take a broader perspective. Figure 1 shows the change over the last 8 years, with a) from April 2014 and b) from April 2022, both the exact same stretch of beach.
This seaweed is Sargassum which reproduces vegetatively and never attaches to the seafloor. The Atlantic Ocean's Sargasso Sea was named after the seaweed for the large amount of Sargassum that collects there. More recently, an area of Sargassum has developed off the coast of Brazil near the mouth of the Amazon River.
Figure 2 from the University of Florida Satellite-based Sargassum Watch System (SaWS) shows how the Sargassum bloom off the coast of Brazil has evolved. Since 2011, Sargassum seaweed has appeared in the Caribbean Sea every summer except 2013, creating many environmental, ecological and economic problems. The seaweed originates in the tropical Atlantic and drifts with the current into the Caribbean. It is believed to be a result of climate variability combined with other natural and anthropogenic processes and has been getting progressively worse. One of those anthropogenic processes is deforestation, which causes soil erosion that leads to surplus nutrients being washed into rivers and flowing into the ocean, ultimately feeding the Sargassum. Deforestation also releases carbon into the atmosphere which contributes to climate change and increases ocean temperature, which then accelerates Sargassum growth.
2018 was a bad year for the seaweed, but April 2022 seaweed quantities have exceeded all prior years. The overall Sargassum amount increased significantly across the tropical Atlantic, the Caribbean Sea, the Gulf of Mexico, and the Central West Atlantic (the region east of the Lesser Antilles), setting a new historical record for the month of April.
How has Cancun been dealing with this problem? Not very well. Although there has been some attempt to clean the seaweed with vessels, most still washes ashore. Figure 3 shows the various ways the individual resorts in the Hotel Zone have been dealing with the problem: a) bury using tractor, b) what's left after burying – "sandweed fluff", c) leaving to decompose naturally – resulting in a prickly mess that is unsightly and uncomfortable to walk on, and d) haul-off using backhoes and dumpsters. Not shown is another common approach - hotel workers burying the seaweed by hand on the beach. They spend all day raking and shoveling and go home exhausted, only to return the next day and start over again. All approaches, other than leaving in place, result in significant cost for the hotels, and all impact the beach. The famous soft, white, pristine Cancun sand no longer exists.
Ultimately, this has an impact on visitors who hear about the problem and choose a different destination or who visit Cancun, are disappointed in the beaches, and choose to not return in the future. According to the Mexican government, tourism will fall by as much as 30% at Quintana Roo (state that includes Cancun and the Mayan Riviera) beach destinations this year due to the invasion of Sargassum.
When organizations try to calculate the cost of climate change, they focus on measurable costs – how much it costs to fight the impact of the change or repair the damage caused. But what about the indirect costs? What is the value to the world of walking on the beaches of Cancun or scuba diving along the Australian coral reefs or skiing in the Andes mountains or living on the coast of almost any place in the world, all (and much more) of which are at risk of disappearing?